This invention relates generally to movable steps for use on vehicles and in particular to a retractable step employing apparatus to prevent sagging of the step and for preventing injury to passengers and objects when being lowered to its operating position.
Retractable steps for mass-transit vehicles utilizing parallegram linkages for connecting the movable step with the fixed member to maintain a parallel relationship between the vehicle floor and the step have been used in the past, however, the linkages are of necessity connected to the rearward portions of the movable step member when movable step is in the retracted position, the leverage relationship and the amount of play in the linkage connections causes the front end of the step to sag below the level of the bus chassis and be damaged by objects encountered on the road and along the side.
Furthermore, the retractable steps of the prior art failed to allow for immovable objects such as a passenger's leg or the like when being extended into its operable position. Failure to provide for such a situation could cause serious injury to a passenger as well as possible costly damage to the step itself and perhaps to the vehicle at the point of attachment of the step to the vehicle.